A hybrid car including an engine actuated by energy on combustion of fuel and an electric motor actuated by electrical energy as power sources for traveling of the vehicle and including an automatic transmission provided between the power sources and driving wheels is in the actual use. In such a hybrid car, by properly using the engine and the electric motor according to a driving state, for example, to travel, it is possible to reduce fuel consumption and an amount of exhaust gas while maintaining predetermined traveling performance. To put it concretely, the hybrid car has a plurality of driving modes with different actuated states of the engine and the electric motor such as an engine traveling mode for traveling while powered by only the engine, a motor traveling mode for traveling while powered by only an electric motor, and an engine plus motor traveling mode for traveling while powered by both the engine and electric motor and automatically switches among these modes according to a predetermined mode switching condition such as a power source map using driving states such as vehicle speed (or power source rotation speed) and an accelerator operated amount as parameters.
Some of such hybrid cars have an EV drive mode (hereafter the EV drive mode and an EV mode will not be distinguished from each other) in which a driver can push a selecting switch (referred to as an EV drive mode switch or an EV switch, for example) to restrict actuation of the engine and achieve traveling by only the motor in order to reduce noise in a midnight or early-morning residential area or reduce exhaust gas in a garage. However, if catalyst temperature of the engine, vehicle interior temperature, or HV battery temperature is low, if a heater or a defroster is used when temperature of engine cooling water is low, or if SOC (State of Charge) of an HV battery is low, it is impossible to execute the EV drive mode.
A hybrid car control device disclosed in Japanese Patent Laying-Open No. 2000-204996 includes an engine and a motor for transmitting power to wheels, a plurality of modes for driving at least one of the engine and the motor can be set and one of the modes is selected based on predetermined conditions. The hybrid car control device has an engine control unit for selecting a mode for prohibiting or restricting starting of the engine in a situation, irrespective of the predetermined conditions, where starting of the engine in the stopped state is not desirable.
With this hybrid car control device, the mode for prohibiting or restricting starting of the engine is selected irrespective of the predetermined conditions in the situation where starting of the engine in the stopped state is not desirable. In other words, the mode selection reflects a driver's will.
However, even with the above-described hybrid car control device disclosed in Japanese Patent Laying-Open No. 2000-204996, the following problems may occur.
In normal cases, it is possible to select the mode for prohibiting or restricting starting of the engine after completion of system startup of the hybrid car. If a time interval between the system startup and starting of the engine is as long as a certain period (e.g., 10 seconds), the driver can avoid starting of the engine by pushing the EV switch during the time period. However, a condition for starting the engine is satisfied (e.g., avoidance of a shock of the engine starting and warming up of the engine catalyst) immediately after the system startup, the engine may be started immediately after the system startup. In such a case, the engine is started against the driver's request to avoid starting of the engine. This occurs when the system is started up in the hybrid car with the non-operating system in the above-described midnight or early-morning residential area. Even though a system startup switch (referred to as a start (ST) switch or a power switch) is pushed and the EV switch is pushed, the request for the EV traveling is recognized by an ECU (Electronic Control Unit) only after satisfaction of the engine starting condition and the engine is started immediately after the system startup.